Question

what do you mean by alkali .from chapter acid base and salt​

Answer 1

Answer:

Alkali is a basic hydroxide or ionic salt which is soluble in water. All bases are not alkali. They turn red litmus paper to blue having pH value greater than 7.

An alkali is derived from the Arabic word 'qali' means ' from the ashes'. As ashes are mixed with water used for cleaning products and are made of alkali materials.

It is a basic hydroxide or ionic salt of an alkali metal or alkaline earth metal element which is soluble in water. They are strong bases that turn red litmus paper to blue; they react with acids to form salts. Examples are sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide etc.

more to know;

Do you know that during the digestion of food in the stomach an alkaline liquid known as bile is added to neutralise the aciditiy of stomach so, that the mixture of food, bile and enzyme turned into an alkaline solution. The enzymes in the small intestine work properly at the pH of 12. Alkali metals belong to group I of the periodic table.

Answer 2

$\underline{\textbf{QUESTION :-}}$

what do you mean by alkali

$\underline{\textbf{ANSWER:-}}$

Alkalis:

Alkali term is used to describe the aqueous solution of a base. For example the ‘aqueous solution’ of sodium hydroxide is an alkali. Similarly, the aqueous solution of ‘potassium hydroxide’ is also an alkali that has hydroxyl ions in its solution.  

We can say that all basic compounds when mixed with water to form aqueous solution form alkali which have free hydroxyl ions in it.  

Alkalis are water-soluble bases. Some of them are:-

1. Sodium Hydroxide
2. Potassium Hydroxide
3. Rubidium Hydroxide
4. Cesium Hydroxide
5. Francium Hydroxide

$\underline{\textbf{EXTRA INFORMATION:-}}$

Acids :

• The term acid is derived from a Latin word ‘acidus’ or ‘acere’, which means sour. The most common characteristic is their sour taste. An acid is a substance that renders ionizable hydronium ion (H₃O⁺) in its aqueous solution. It turns blue litmus paper red. These dissociate in their aqueous solution to form their constituent ions, as given by the following examples.

• Based on their occurrence, they are divided into two types- Natural and mineral acids.

Types of acids

1. Natural Acids: These are obtained from natural sources, such as fruits and animal products. For e.g. lactic, citric, and tartaric acid etc. Mineral Acids:
2. Mineral acids are acids prepared from minerals. For example, Hydrochloric acid (HCl), Sulphuric Acid (H₂SO₄), and nitric acid (HNO₃) etc.  
3. Dilute acids: Dilute acids contain a large amount of water. A concentrated acid can be diluted with the addition of water.

Bases :

• The most common characteristic of bases is their bitter taste and soapy feel. A base is a substance that renders hydroxyl ion(OH⁻) in their aqueous solution. Bases turn the colour of red litmus paper to blue.

• A substance used to neutralize acid is called a base.

• Some of the bases that form a neutral product with acids are metal hydroxides and metal oxides.

• Examples of base: zinc hydroxide and copper oxide.

• Base reacts with the acid in order to make it neutral.

• The base is bitter in taste and is slippery in nature.

• They produce salt molecules and water on reacting with acids.

• Types of bases are a strong base and a weak base.

• Example of a strong base is NaOH.

• Example of a weak base is NH³.

• Bases do not dissolve in water.